The proliferation of radio-frequency based technology, such as cellular telephones, RFID devices, and other wireless devices, has led to a number of developments in antenna design. One popular antenna type is the patch antenna, whereby a radiating patch is positioned parallel to and spaced apart from a ground plane. A dielectric substance is placed between the patch and the ground plane. Signals may be provided to the patch, and incoming signals may be obtained, through a feed mechansim. Typical feed mechanisms for patch antennas include one or more coaxial feeds extending through the dielectric material, or an embedded planar feed line connected or electromagnetically coupled to the patch, or an aperture coupled feed.
At present, standards have been developed that apply to communication in a number of different frequency bands, sometime for different purposes or applications. Example standards include GPS, GPRS, 2.4 GHz WLAN, 5.8 GHz WLAN, and the new 5.9 GHz DSRC (Dedicated Short Range Communications) bands.
Existing patch antennas have difficulty in achieving certain desirable characteristics, such as vertical polarization relative to a horizontal patch position, uniform radiation pattern in azimuth, or significant antenna gain at zero elevation degrees (or θ=90°), i.e. in the horizontal plane of the antenna.
It would be advantageous to provide an improved patch antenna.